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Tunable Elastomeric Nanopores

G. R. Willmott, M. F. Broom, M. L. Jansen, R. M. Young, W. M. Arnold
Molecular- and Nano-Tubes, 2011, pp 209-261

A general introduction to tunable elastomeric nanopore technology is presented. Tunable nanopores have been used to detect particles ranging from dsDNA to 10 μm diameter spheres using the resistive pulse method. These nanopores are formed in thermoplastic polyurethane by mechanically puncturing a membrane with a sharpened tungsten probe. Optical microscopy, AFM and SEM demonstrate that the pores are near-circular cones. The fabrication process, actuation mechanism and key material properties such as viscoelasticity and failure mechanisms are described. Ionic current-voltage experiments, in which membranes are stretched to ∼30% strain and relaxed, are used to demonstrate reversible actuation of the estimated smaller pore radius over an order of magnitude. Actuation characteristics are compared with simple analyses and modelling of the stretching process. These nanopores are efficient and versatile when compared with similar technologies. Virus sensing is the most immediately appealing application; this and other applications are discussed, along with directions for future work.

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